Cylinder apparatus

Abstract

A cylinder apparatus comprises a cylinder tube which is connected between a first cover member and a second cover member each having a cylindrical configuration, an axially displaceable piston which inscribes the cylinder tube, a piston rod which is connected to the piston, an intermediate member which is connected between the cylinder tube and the second cover member, an axially movable member which inscribes the intermediate member, a first spring member which is connected between the second cover member and the movable member, and a piston pin mechanism which is inserted into a recess of the piston rod in a direction perpendicular to the axis.

What is claimed is:  
     
       1. A cylinder apparatus comprising: 
       a cylinder tube which is integrally connected between a first cover member and a second cover member;  
       a piston which is installed in said cylinder tube and which is axially displaceable in said cylinder tube;  
       a piston rod which is connected to said piston;  
       an intermediate member which is connected between said cylinder tube and said first cover member or said second cover member;  
       an axially movable member which inscribes said intermediate member;  
       a spring member which is interposed between said first cover member or said second cover member and said movable member; and  
       a fastening mechanism which includes a pin section for holding said piston by being inserted into a recess of said piston rod in a direction substantially perpendicular to the axis of said cylinder apparatus,  
       wherein when said piston reaches a displacement terminal end position, an axial length of a space is shorter than an axial distance between a side surface of said recess of said piston rod and a side surface of said pin section of said fastening mechanism, said space being defined between said intermediate member and said movable member.  
     
     
       2. The cylinder apparatus according to  claim 1 , wherein said intermediate member has a first annular projection protruding radially inwardly, said movable member has a second annular projection protruding radially outwardly, and said space is formed between said first annular projection and said second annular projection. 
     
     
       3. The cylinder apparatus according to  claim 2 , wherein when said piston reaches said displacement terminal end position, said piston returned toward another displacement terminal end position is displaceable by said axial length of said space. 
     
     
       4. The cylinder apparatus according to  claim 1 , wherein said fastening mechanism is a piston pin mechanism, said piston pin mechanism including a main body section which is installed to an outer circumferential surface of said first cover member or said second cover member, a pin section which is supported by said main body section, and a second spring member which is interposed between said main body section and said pin section. 
     
     
       5. The cylinder apparatus according to  claim 1 , wherein a first pressure fluid inlet and outlet port and a second pressure fluid inlet and outlet port are formed in said first cover member and said second cover member respectively, a pressure fluid being supplied through a five-port solenoid-operated valve to said first pressure fluid inlet and outlet port or said second pressure fluid inlet and outlet port. 
     
     
       6. The cylinder apparatus according to  claim 1 , wherein said cylinder apparatus further comprises a driving force-transmitting mechanism, said driving force-transmitting mechanism including a joint member which is connected to said piston rod and which converts the rectilinear motion of said piston rod into the rotary motion, a rotary member which is rotatable about an axial center thereof, a key section which is formed on said rotary member and which is inserted into a key groove of a workpiece, and a link section which transmits said rotary motion of said joint member to said rotary member.